Up to now, there are vertical SiC semiconductor film forming apparatuses that epitaxially grow an SiC semiconductor while supplying an Si raw material gas or a C raw material gas from above the SiC semiconductor substrate. In the vertical SiC semiconductor film forming apparatus of this type, for the purpose of improving the uniformity of a film thickness and a concentration, for example, a method of introducing the raw material gas with the concentrations of the respective raw material gases and a C/Si ratio kept uneven is employed. However, in the SiC semiconductor growth apparatus into which the raw material gases are mixed together and introduced, the Si raw material gas and the C raw material gas react with each other in a space before those raw material gases are introduced into a furnace body of the growth apparatus, and an unnecessary SiC product is formed on an introduction part and a wall surface into a particle source. This causes such a problem that a film quality of the SiC semiconductor epitaxially grown is deteriorated.
For that reason, Patent Literature 1 has proposed a method of isolating the Si raw material gas from the C raw material gas as a method of restraining the unnecessary SiC product from being formed. Specifically, in Patent Literature 1, a supply path for supplying the Si raw material gas is extended at a center position of the SiC semiconductor substrate, multiple openings for supplying the C raw material gas are provided around the supply path, the Si raw material gas is supplied from the center, and the C raw material gas is supplied from around the center.
However, in Patent Literature 1, a supply position of the Si raw material gas is fixed to the center position of the SiC semiconductor substrate, and a supply position of the C raw material gas is fixed around the Si raw material gas. The number of supply paths is formed at each location. For that reason, a raw material concentration distribution and a distribution of the C/Si ratio in a plane of the SiC semiconductor substrate cannot be controlled, and the in-plane uniformity of the thickness and the concentration of an epitaxial film cannot be controlled. Therefore, there arises such a problem that both of the suppression of particle generation and the in-plane uniformity of the film thickness and the concentration are not performed in the epitaxial film.